In a statement to the Associated Press, Kidder's daughter Maggie McGuane said the family decided to make her mother's suicide public because "it's important to be open and honest about the suicide so there's no cloud of shame".

Initial reports of Kidder's death in May said that she died in her sleep of natural causes, as The Inquisitr reported.

Kidder's daughter said she knew her mother died by suicide the moment authorities took her to Kidder's home. She believes it is important to be open and honest about suicide and not hide it.

While no further details will be released of her suicide, McGuane added that "it's a unique sort of grief and pain and that she would like to reach out to every family who is suffering through a loss by suicide". "It's a big relief that the truth is out there", McGuane tole the news agency.

Joan Kesich, a longtime friend who found Kidder's body, spoke to Margot's battle with mental health issues, saying she was fearless and always spoke the truth, regardless of the consequences.

Kidder was born in Canada and spent decades acting in movies and television shows before and after Superman, including Some Kind of Hero, The L Word and Smallville. I want what I know about her to be out there because it was glorious.

Kidder became one of Hollywood's first and most prominent mental health advocates.

Both Kidder and co-star Christopher Reeve, who played Superman, were relative unknowns when they got their leading parts, and neither saw many major roles afterwards.

The actress died at the age of 69 at her home in Livingston, Montana, on 13 May.